Omron SYSMAC CP Series, User Manual

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14 Serial Communications
14-14
CP2E CPU Unit Software User’s Manual(W614)
14-4 Modbus-RTU Easy Master Function
Using the Modbus-RTU Easy Master enables easy control of Modbus-compatible slaves, such as
inverters, using serial communications. The serial communications mode is set to Modbus-RTU Easy
Master.
Modbus-RTU commands can be sent simply by turning ON a software switch after setting the Modbus
slave address, function, and data in the DM fixed allocation words for the Modbus-RTU Easy Master.
The response when received is automatically stored in the DM fixed allocation words for the Modbus-
RTU Easy Master.
14-4-1 Overview
14-4-2 Flow of Operation
1
Connect the CP2E CPU Unit and Modbus-RTU Slave
using RS-2
3 2C or RS-422A/4 8 5 ports.
2
Select Built-in RS-2 3 2C , Built-in RS-4 8 5 or Serial Port in
the PLC Setup and transfer the PLC Setup from the CX-
Programmer to the CP2E CPU Unit. (Set the serial com-
munications mode to Modbus Easy Master, and set the
communications conditions.)
3
• Set the Modbus-RTU frame in the DM Fixed Allocation
Words.
• Turn ON the Modbus-RTU Master Execution Bit
(A640.00, A641.00 or A6
38 .00).
Mod bus -RTU
15 08 07 00
D1200
- -
D1201
- -
D1202
D1203
Comm u nic a tion s a re e as ily a chieved
b y s imply t u rning ON A640.00 a fter
s etting the Mod bus -RTU comm a nd in
the DM fixed a lloc a tion word s .
Mod bus -RTU M as ter Exec u tion
Bit for Port 1 A640.00
CP2E CPU Unit
S l a ve a ddre ss
S l a ve a ddre ss
S l a ve a ddre ss
F u nction code
F u nction code
F u nction code
Comm u nic a tion s d a t a
Comm u nic a tion s d a t a
Comm u nic a tion s d a t a
OMRON Inverter s
3G3MX2-V1, 3G3RX2,
3G3RX-V1
N u m b er of comm u nic a tion s d a t a b yte s
~
W iring comm u nications
PLC Set u p
Create
ladder
Program
Cyclic tasks
Interr u pt tasks